Film shoe



June 1.7, 1947.

o. R. YNEMETH FILM SHOE Filed May 22, 1944 jiwenzor Oz'ig fikNenwt/vPatented June 17, 1947 UNI-T ED: STATEPSE ornces:

mesne assignments wto Helene Curtisihulusf tries, Inc a corporation ofIllinois- P v Ap 'alication May 22,1944, Seria1Nb;" 536;726 4 Olaims:1-.-(Cl. 271- 2:3)"

Thisinventionnrelates to improvements in: mom" 1 ingupicture apparatusandimoref particularly-hon cerns fa novel film shoe'rfconstructiom:iofmain' tainingsa, film strip in planaupon an associatedifi1m:sprocket:

An important :o bject of the zpresen't "invention is to providea:newandrimproved fiimrshoeiconum struction of :simple; durable-and.compact'=- con-rr= structi-on anda-which is exceptionally eflicientandconvenient ion the intended purpose;

Another object is to provide :a:filmshoe'rwhichw/ in the cpenrornon-operating ciondition 'assum'es a position behind the film path:andzafiords max-' imum' working clearance at the iront'ofthewfilmiisprocket,---thus: great-1y facilitating threading: of thefilm. I =Henc'e, the invent-ion sharply; -distin-- l guishesfromconstructions-in which the film shoe is moved onlyradiall-yortangentiallyaway -from.-=- the film sprocket-a limited distanceresultinghin a crowdedconditioneof the-apparatus and olo-- 2ostructingefreedom of manipulationcf the :film or e of access to othermechanism in thevicinitzv ofthe film sprocket-w;

Anotherobj ect :resi'des'. in the. iprovision of im-v proved :means. forpositively retaining: the film 1525 shoe in operating Fornonoperating"position? butv-l enabling quickrand :easy manipulation ofthe film Y, shoe into either of such positionsms Still another object ofthe invention is to pro-* vide a filmsshoe which isadjustabler'withrespect to its .operativeappruachto thesfi-lmsprocketi Afurther object :isto provide an improved film-Wshoe=construction.involving at minimumnumben i of simplecomponents whichareparticularly sus-M ceptibIeLo-f 10W costqixantityproduction .meth-HBSods of manufacture Other objects,- features, andadvant'ag'es .oi theinvention-.wiIL be apparent fromthe following descriptionanditheiaccompanying' sheet of drawingsiinwhich'z u Figiirelxi aperspective view. of a film shoe' and film sprocket assembly'embodyin'g'the' fea' turesxof the present invention;

FigTZ is a front elevaticnal vieW' o-f the 'film'l shoe and sprocketassembly.

FigLBis a longitudinal vertical sectional view.

throughthe film shoe and sprocket assembly". 1 taken substantially inthe plan'eof line 3-3 of Fig. "2 but showing the "fi1m"shoe in the-"openor non-operating position Fig; 4, is a vhorizontal sectional view takensubstantially in theilplane of line 4-4 of FigI -Z.

Having. more particular. reference'to the draw-' ing the :specific Iembodimenmof the invention 3 selected for illustration 'isespe-ciallyedapted ion 1a castinig havinean-integral journal bos's miii-'0 2 L: use 'in therelatively sma ll hom'e' type o'f pm jector suchas employslG mm; filnii but obviously theinventi'oncanbe employed w itlm oi any size by "eXerci-s'e of simple mechanical adapta tion Accordingto the' inventioiig a filmshoe' til as 5 cooperatively *associated witha film spro'clre't ll i andboth 'are-operatively mounted to p'roqect outfroma mounting plate 12. Th'e 'latter may be jecting to o pesite sidesof the' plate 'a nd r iro videdewithi an iaxial bbre rMJI-'lBearingsret5 may be pressfitt'ed inter-the oppositezends of the-borerMA A shaft l'l rotatablysupported by the-I'b'ear ings "I5 extends beyondthe epposite ends of them boss 13 and carries the film sprocket IIkeyed? onto its front' 'end: while 1 a driving 1 pinion or sprocketgear-r l-fi is keyed to ithe 'opp0site'end w of the shafta FPoWerfordriving thewshaft -vlz'l zand 'thereby the -sprocket H rotatably-istransmittcdthroughathe geer l8 in anysuitable manenemas by means-ofachainflnohshownla As best i'seerr in 3, the =portion-of theej'ournalboss |3 extend-ing to the front' of the mounting iplatel2 affords asubstantial operating: cleanancabet-ween the adjacent tace-cf themounting plate and the adjacent end of the fih'flSIlPOC-kfpl t. At:itsinner'end' the sprocket ll has a radialfilm :locating' 1 and:retain-irig :fiange'vi 9, forwardly of but adjacenttn 'Whi'Ch iS aseries of -radia1-:= sprocket; teeth-2fl edaptefd'to engage -in conventional marginal sprocket apertures 2 l in a film" strip: 22threadedover"the sp1o'cl et; In this 'instanceflthe film sprocket! I isdesigned-to handlesoundtrack film." 5

By preference'the fi'lm shoe 10 is in the form of an elongated"plateadaptewto lie in centeredlongitudinally parall'el relation to the axisefthe filmsprocket' H when-in film-holding-relation to I thesprocket.-T0this end,'the film'shoeisformed with: atransversely -concaveundercut--23, having'fi a curvature which is complementary l to and con"centric-with the sprocket- 11 in the opera-tingpo':-- sitionof thesh0e.- "The :lengtho-f the under-61117 23 is sligh-t-ly-greaterthanthe-length of: thesprecket hold-down H shou1der$ 28 and 29,respectivel'y, "I

3 which project concentrically slightly from the main recessed arcuatesurface of the undercut 23 to oppose the extreme margins of the filmstrip 22 and confine the film 22 to or quite close to the periphery ofthe film sprocket H. Thus the film 22 is guided for travel substantiallycentered in the film track.

By reference to Fig. 2 it will be observed that the width of the filmshoe IQ, or more properly the arc of the concave undercut 23 ispreferably equal to and opposes a section of roughly from one-fourth toone-third of the circumference of the sprocket. This affords quite amplefilm retaining or confining area in the shoe while at the same timeaffording ample freedom for substantial range in the preferredtangential angles of approach or recession of the film. Additionaltolerance in this respect is contributed by preferably smooth ogeecurved contouring to the longitudinal edges of the shoe.

Adjacent to its rear end the film shoe Iilis hingedly mounted upon themounting plate l2 to enable swinging the shoe into and out of filmholding relations to the film sprocket ii. For

this purpose a hinge pin 30 extends transversely through the rear end ofthe film shoe IE3 and through a pair of spaced hinge lugs or ears 3!formed integral with the mounting plate 12 and appropriately located toproject forwardly and receive the film shoe in longitudinally mediallycentered relation to the film sprocket.

In order to facilitate swinging the film shoe into and out of operativeposition, an integral forwardly projecting handle or finger hold 32 maybe provided at the forward end of the film shoe.

Although the film shoe i0 is freely hinged, its swinging movement issuitably controlled in an improved manner through the medium of a leaftype tension spring 33. Herein the spring 33 is formed with an enlargedmounting head 3 which is appropriately apertured to receive the shank ofa securing screw 35 by which the spring is fastened against a mountingpad 37 on the mounting plate I2 in centered relation adjacent to'therear end of the film shoe 1 0. Extending at a preferably outwardlyslanting angle from the mounting head 34 of the spring is an integraltension leg 38 which projects into a spring clearance recess or cut out39 bifurcating the rear end portion of the film shoe l0. Traversing thisbifurcation 39 forwardly of the hinge pin 38 but relatively close to thelatter is abutment means such as a pin d0 against which the free endportion of the spring tension leg 38 bears with constant resilientpressure. The location of the abutment pin 48 relative to the springtension leg 38, and the approach of the spring tension leg to theabutment pin are such that in the closed or operative film-retainingposition of the film shoe ID, as seen in Figs. 1, 3 (broken lineposition) and 4, the spring pressure against the pin i!) is translatedinto an over-center force tending to urge the film shoe about its hingepivot firmly toward the film sprocket II. This positively, thoughresiliently, maintains the film shoe in the operative position.

When the film shoe If! is swung away from the film sprocket H for filmthreading purposes or the like, the abutment pin 45] also swings on ashort are about the axis of the hinge pin 30, and after the film shoehas been opened to the. extent that the pin 40 passes beyond the centerof resilient force as indicated by the line C in Fig. 3,'the spring 33holds the film shoe open. The

film shoe Iii will then be retained in the open position until pushedback to the operating overcenter side of the line C whereupon the springtension acts to snap the film shoe closed. 7

Although the primary function of the film shoe H1 is to hold the filmstrip 22 in close engagement with the film sprocket l l theshoe-sprocket inter-relationship must be free from drag, such as wouldbe imposed by the relatively stationary film shoe were it to pressagainst the film upon the sprocket under the influence of the spring 33.Accordingly, stop means is provided for maintaining the film shoe isoperatively spaced from the periphery of the film sprocket to affordclearance for the film to move freely between the film shoe and thesprocket while nevertheless confining the film close to the sprocket.Herein such means comprises a stop element 4| in the form of an'adjustment s c r e w threaded perpendicularly through the film shoe l0intermediate the flange groove 25 and the spring clearance 39 and adapted to abut against a bearing pad 42 on the adjacent surface of thejournal boss l3. Through the medium of the adjustment stop screw 4!, anoptimum film clearance spacing can be attained between the film sprocketI I and the film-opposing shoulders 28 and 29 of the film shoe. Suchspacing should, of course, be conditioned to accommodate a film splice.Any adjusted condition of the stop screw H can be maintained by' meansof a lock nut d3.

By preference, the adjustment stop screw 4| serves also to stop ordelimit the fully open position of the film shoe l B. For this the headof the screw 4! is preferably so disposed relative to the tension spring33 that when the film shoe I0 is swung far enough open the head of thescrew may engage the adjacent face of the spring and resist furtheropening of the shoe.

While I have illustrated and described a certain preferred embodiment ofmy invention, it

is to be understood that I do not thereby intend to limit my inventionto the specific form disclosed, but contemplate that variousmodifications, substitutions, and alternative constructions may beeffected without departing from the spirit and scope of the invention asdefined in the appended claims:

I claim:

1. In combination in a film shoe construction, a film shoe bodyincluding means for cooperation with a film sprocket to hold a filmstrip in place upon the sprocket, means for hingedly mounting 1 the shoefor swinging. into and out of operative positions relative to the filmsprocket, an opening in said body adjacent to said hinge means, anelongated leaf spring adapted to be mounted adjacent to the hingemounting of the shoe and having a tension leg adapted to extend intosaid opening, and means in said opening providing a bearing for saidtension leg to receive resilient thrust therefrom operative to hold theshoe in open or closed position when the shoe is selectively moved intoeither of said positions.v

2. A film shoe construction as defined in claim 1 in which the shoe bodyis of elongated form and bifurcated to provide said opening and thebearing means comprises a pin extending across the bifurcation.

3. In combination in a film guiding construction of the characterdescribed, a film sprocket, a film shoe cooperative with the sprocket toconfine a film strip closely to the sprocket in running thereover, ahinged mounting for said shoe enabling swinging thereof into and out ofoperative positions relative to the sprocket, means on said shoelimiting movement of the shoe into 0D- erative position, and anelongated leaf spring cooperative with the film shoe to maintain itresiliently in either the operative or inoperative positions, andmounted in angular relation to the shoe opposing the body of the latterwhen in said inoperative position, said means coacting with the springto restrain the shoe to a predetermined extent of movement into saidinoperative position.

4. In combination in a film shoe construction adapted to be associatedwith a film sprocket, means for hingedly mounting the film shoe at oneend to enable opening and closing movement of the shoe relative to theassociated film sprocket, an elongated leaf spring mounted adjacent tothe hinge mounting of the shoe, said film shoe having an opening thereinaffording clearance for receiving said spring, and means on said shoeinwardly from the hinge mounting thereof and bridging said openingengaged by said spring, the inter-engagement of the spring and saidmeans being such that the force of the spring against said means exertedon one side of a given plane through the hinge axis causes the shoe tobe urged toward the film sprocket, and force exerted by the springagainst said means on the opposite side of said plane retains the shoein an open position.

OTTO R. NEMETI-I.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

